Tycor Core Material?

[RocketFeller]

I have some 15mm Tycor core material on its way for a big rocket I'm doing with some of my students. Has anyone used this product? https://tycor.milliken.com/Pages/products-tycorW.aspx

It is a fiber reinforced foam core used for wind turbine blades. Last year we used 1/2" end-grain balsa, I'm very eager to see how this stuff compares. It will be covered with carbon fiber to form sandwich panels. We plan to use it for the fins (fully wrapped in CF), centering rings, bulkheads, and internal structure of a large rocket.

 

[RocketFeller]

I received the core material today. It looks interesting, it is composed of foam squares with fiberglass roving on the surfaces and between the squares. I can't wait to have it covered in carbon fiber.

 

[mad4hws]

I received the core material today. It looks interesting, it is composed of foam squares with fiberglass roving on the surfaces and between the squares. I can't wait to have it covered in carbon fiber.

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I am interested in how this will turn out. do you know how thin they make this stuff? 15mm is still a little thicker than I would want. What size airframe are you going to be using and how many layers of CF?

thx
don

 

[RocketFeller]

I am interested in how this will turn out. do you know how thin they make this stuff? 15mm is still a little thicker than I would want. What size airframe are you going to be using and how many layers of CF?

thx
don

I'm not sure how thin, on their website it says that it comes in "standard core thicknesses", for all it's worth.

This will be for a 15" (Polecat) airframe. I am not positive about how many layers and of what weight. We are working with a local manufacturer of CF plate/sheet material. we are looking for ~1mm or a bit less for the finished CF faces. They will be vacuum bagged as whole sheets and then the fins/rings cut out on a CNC. We will edge the fins using strips of CF plate, the rings/bulkheads won't need edging.

I really like the ways the fibers tie the two faces of the composite sandwich together, they claim it gives improved strength properties over plain foam/balsa.



From their website:

TYCOR® G
Our fiber reinforced composite cores use advanced three-dimensional fiber architecture and cost effective automated manufacturing processes to produce lightweight, high strength, robust sandwich structures for a range of applications including truck bodies, railcar decks, military shelters, bridge decks, temporary runway matting and cargo ship freezer floors.

TYCOR G has the structural properties to support concentrated and high shear loads that conventional balsa and foam core products just can’t handle. TYCOR G enables better design solutions and is optimized for greater cost efficiencies. Specifically designed for resin infusion processes, TYCOR’s infusion grooves allow the resin to move quickly and efficiently throughout each panel ensuring high quality infusion of the sandwich panels’ internal structure. TYCOR G can also be tailored to meet unique performance specifications.

Key Performance Advantages
TYCOR performs effectively in flat shapes with less resin absorption than foam and balsa cores. TYCOR is offered in standard core thicknesses to give designers and manufacturers the flexibility to optimize product designs. Milliken is also able to tailor modifications for individual specifications.

•• High strength and stiffness
•• Greater durability
•• Lower Weight
•• Lower resin costs
•Superior damage tolerance
•Optimized for greater cost efficiencies
•Higher quality
•Can be tailored to custom specifications

https://tycor.milliken.com/Pages/products-TYCORG.aspx

 

[dhbarr]

From poking their datasets, looks like 10-12mm is as thin as they go ( except they also sell pre-tapered ).

 

[emckee]

I'm not sure what you'll gain here vs a foam core CF laminate. It will largely depend on how you apply epoxy to the structure.

Fins would be my biggest concern: Compressive and tensile stresses will be highest at the surfaces, which is where your CF will be - no issue. But shear loads between the fin sides will be borne by the core material. If the FG woven through the core is not set in a matrix, it's going to flex and move enough so that it will provide no real support. Further, the core is made up of individual blocks which can move past eachother, exacerbating the issue.

The CF plate at the edge will provide some support vs shear... I suspect that the challenge will be the bond between CF edge plates and the core material, if not the bond between edge and face sides. (my mind's eye pictures your Dragonfly fins)

It occurs to me that the Tycor blurb points out that the design is to support high shear loads, but I suspect their load model applies a normal force to the flat panel of the board, rather than applying a shear force in plane with the board. In a highly anisotropic material, such as this, the properties will be anything but homogeneous.

My engineering side wants you to make specimens for testing... foam core with CF wrap, foam core with sides and edge plated in CF (not wrap), and same with the Tycor boards. Then stick them into a load cell and test to failure. *grin*

But there I go trying to teach the teacher! With a 15" airframe, chances are you're not going to be putting terribly high aerodynamic loads on these fins, in any case.

I thought you guys were going to go for 100k altitude next? Change of plans?

 

[RocketFeller]

I'm not sure what you'll gain here vs a foam core CF laminate. It will largely depend on how you apply epoxy to the structure.

Fins would be my biggest concern: Compressive and tensile stresses will be highest at the surfaces, which is where your CF will be - no issue. But shear loads between the fin sides will be borne by the core material. If the FG woven through the core is not set in a matrix, it's going to flex and move enough so that it will provide no real support. Further, the core is made up of individual blocks which can move past eachother, exacerbating the issue.

The CF plate at the edge will provide some support vs shear... I suspect that the challenge will be the bond between CF edge plates and the core material, if not the bond between edge and face sides. (my mind's eye pictures your Dragonfly fins)

It occurs to me that the Tycor blurb points out that the design is to support high shear loads, but I suspect their load model applies a normal force to the flat panel of the board, rather than applying a shear force in plane with the board. In a highly anisotropic material, such as this, the properties will be anything but homogeneous.

My engineering side wants you to make specimens for testing... foam core with CF wrap, foam core with sides and edge plated in CF (not wrap), and same with the Tycor boards. Then stick them into a load cell and test to failure. *grin*

But there I go trying to teach the teacher! With a 15" airframe, chances are you're not going to be putting terribly high aerodynamic loads on these fins, in any case.

I thought you guys were going to go for 100k altitude next? Change of plans?

Believe me, I have lots to learn!

The blocks are actually bonded together. It is definitely reminiscent of the butcher-block construction of the end-grain balsa that we used previously. I believe that they may make a bendable version for creating curved surfaces, but this is a flat panel.

Bonding the edging may be tricky, but it should be easier than the Dragonfly's. The elliptical shape required bending the CF veneer around the edge, because of this we ended up using auto-body contact cement to attach the edging. This rocket will have trapezoidal fins. The current thought is to cut CF strips (~1mm thick) that are slightly wider than the thickness of the fins. We will epoxy them on and then sand them to size. Another option would be to cut the fin cores from the core material, round the edges with a router, and then apply the carbon fiber.

We will be laminating the fins at Protech Composites, so I am confident that they will be properly saturated. We have some extra end-grain balsa that we will have laminated at the same time. The plan is to cut some strips from both and do destructive testing to compare the two. If I can find some standard foam core it would be cool to compare all three. In the absence of a load cell we will probably suspend a bucket from a sample between two desks and fill it with weights until the sample breaks. I will bring one of the boards with me on the 12th to show-and-tell.

As far as the high-altitude rocket, it is still in the works for next year. I have been thinking that I should probably get my L3 prior to that, so that is what this would be for. Big slow rockets are what I know, so I figured it would be the prudent path to Level Three. I am hoping to end up with a 15" rocket that weighs less than a lot of 6" rockets....